Technical data

MKA4CAT0UKAG4MG/Rev. 1-01/2009
03
3. DEVICE DESCRIPTION
3.1 Components/blocks pure sinusoidal waveform. Batteries supply the energy and the
Both filters work even if the unit is
user can see the estimated battery
CHARGER
working in bypass mode.
runtime by using the software or the
The charger includes a temperature
LCD display.
compensation which regulates the 3.2 Operating modes
charging process.
When the mains
BYPASS MODE
START-UP SEQUENCE
voltage is within tolerances, the charger In this case, the load is directly fed from
When the unit is connected to the
provides a nominal recharge current up the AC mains. It can be forced by the
mains, it automatically starts to work in
to 1.2A to the batteries. This element is user or activated automatically by the
bypass mode and thus powers
current-limited; therefore, it can only UPS when detecting an overload or
connected loads. To switch to line
provide the nominal current, although other internal failure. This is also the
mode, the user
must press the inverter
batteries may demand more current. start-up mode.
On/Off button. After inverter
Typical recharge time for internal
disconnection through the On/Off
ECO MODE
batteries is 4 hours (for 90% recharge).
button, the unit returns to bypass mode If this mode is enabled, the unit will
whenever the mains is
present. work in automatic by-pass when mains
INVERTER
This sequence allows the load to be fed
The inverter consists of a half-bridge is within tolerances. Otherwise, it
whenever possible.
topology which uses high frequency automatically switches to line mode (if
switching technique. possible, as the voltage input window is
LINE MODE
The inverter is
protected against output
wider in line mode) or to battery mode.
In use, the input AC is converted to DC,
short-circuits and is current-limited.
A very high efficiency (up to 97%) is
and converted back to a pure sinewave.
achieved in this mode of operation.
It prevents the load from suffering
LOGIC CONTROL BASED ON DSP
Logic control provided by a powerful power line problems (including total
FREQUENCY CONVERTER MODE
Digital Signal Processor (DSP) shall loss of input AC power) and corrects
The unit operates as a frequency
sample the output voltage, the load power factor.
converter, providing 50 or 60 Hz
at
The inverter is constantly synchronised
immediately detecting abnormal
output when the input frequency is
with the input line, thus allowing load
voltage conditions and then operating
within 40-70 Hz. There is a power de-
transfer from the inverter to the bypass
the appropriate commands.
rating (50%) when using this mode.
line to power the load in case of
ECO mode and by-pass mode are not
PFC CIRCUIT
overloads or inverter stops.
accessible from this mode.
The power factor correction circuit
provides a very high input current BATTERY MODE
The user can activate/deactivate
UPS switches automatically to this
power factor (~0,99), thus reducing
the
several of these operating modes via
mode when detecting a mains failure
input disturbances and optimizing the
LCD Display.
(and the unit is not in bypass mode).
energy usage. It also contributes to
avoid the introduction of
disturbances upstream.
BOOSTER
Thanks to this element, the
batteries’ voltage is
increased up to
DC bus
voltage for the inverter to
provide the pure sinusoidal
output when the unit is
working on battery mode.
FILTERS
On the one hand, the input
filter reduces disturbances
coming from mains and sets
up the signal for the PFC
circuit.
On the other hand,
inductances at the inverter
output, together
with output
capacitors, act as a filtering
element to obtain the output
Filter
PFC
Charger
Booster
Inverter
Filter
L
N
L
N
E E
+V
-V
-
+
Bypass Mode
Line Mode
Battery Mode
MASTERGUARD Series A
UPS from 700 VA to 3000 VA